It is proposed that limited proteolytic degradation of aorta proteoglycans may be an important predisposing factor for atherosclerosis. Before this hypothesis can be properly tested, the distribution of proteoglycans in normal aorta will be studied. Major emphasis will be given to raising antibodies specific for aorta proteoglycans and proteoglycan regions. Such antibodies will then be utilized in immunohistological methods for aorta proteoglycan localization and identification, and in the development of radioimmunoassays for quantitation. To determine any abnormality in the amount, distribution or structure of proteoglycans in the early atherosclerotic lesion will be an aim. Unequivocal results may not be obtained owing to the limitations of working with human autopsy material. Therefore a nonhuman primate model of atherosclerosis will also be studied. With evidence that proteoglycan alteration is an early event in atherosclerosis, experiments will be planned to determine what factors are important in the control of proteoglycan synthesis degradation. From such experiments, it may be possible to deduce what metabolic events are likely to predispose aorta proteoglycans to the changes characteristic of athersclerosis.